Cylinder shutoff (function chain), ME-SFI fault code description

AD07.61-P-4000-54BA

Cylinder shutoff (function chain), ME-SFI fault code description

Engine 113.960 from 6/00 with Code (479) Cylinder shutoff



Cylinder shutoff (function chain)

1

Fault code

( Display on generic scan tool)

a Cylinder shutoff ON

P2095 Intake valve for cylinder 2, 3, 5 or 8 is still actuated (-)

b Cylinder shutoff OFF

P209E Exhaust valve for cylinder 5 is not actuated (-)

P209F Exhaust valve for cylinder 2 is not actuated (-)

P20A0 Exhaust valve for cylinder 3 is not actuated (-)

P20A1 Exhaust valve for cylinder 8 is not actuated (-)

2

Fault storage

Activation of the engine diagnosis indicator lamp (EURO3/4)

or CHECK ENGINE (MIL) malfunction indicator lamp 

After expiry of test duration and fault

No activation

3

Checking frequency

Monitoring time

a Continuous with cylinder shutoff ON

B Briefly following switching of cylinder shutoff ON  OFF

4

Fault setting conditions

Combustion misfires or increased irregular engine running (detection by irregular engine running analysis)

5

Check prerequisites

- Engine speed around 500 to 4500 rpm and constant

- Medium, constant load (intake manifold pressure around 200 to 1000 hPa)

- Cylinder shutoff enabled

- No fault in hot film mass air flow sensor, crankshaft position sensor, pressure sensor (intake manifold)

- No fault in cylinder shutoff valve (output stages)

- No fault in oil pressure or oil level

- NO "TWC-damaging" misfires

- Exhaust gas recirculation diagnosis not active

- Safety fuel shutoff not active

- Throttle valve actuator emergency mode not active.

6

Check procedure

a Monitoring whether all intake valves for cylinder 2, 3, 5 and 8 remain closed after cylinder shutoff ON (rocker arm coupling released, coupling pins disengaged).
If not, the actual shutoff cylinders draw the fresh air away from the other cylinders and misfiring results. If too many misfires are detected, cylinder shutoff is then deactivated for a short test period. If no further misfires occur, a fault at an intake valve is assumed to be the cause and the fault is set.

B Monitoring whether all exhaust valves open after cylinder shutoff OFF (rocker arm coupling secured, coupling pins engaged). If not, too many misfires are detected at the corresponding cylinder and the fault is set.
The diagnosis also covers the case where both intake valves for a cylinder do not open.

7



- If the rocker arm coupling of an intake valve jams, considerable engine noise will occur (regular, speed-dependent backfiring into in the intake manifold due to pressure expansion, mainly after switching cylinder shutoff OFF  ON)

- If a fault occurs, the engine diagnosis malfunction indicator lamp is actuated immediately due to the simultaneous active fault detection of a "TWC-damaging" misfire.